Beyond the current long term evolution LTE technology, and first significant improvements (LTE-A), the next generation mobile communications technology 5G is imminent. Regarding 5G, a move to even higher frequencies and larger bandwidths are to be expected. Although the exact frequency bands are not yet specified, frequencies up to 75 GHz are in discussion. For reaching sufficient ranges using these frequencies, the antenna technology is a core aspect. High antenna gains are necessary. In order to reach such high antenna gains, the use of antennas with a large number of radiating elements, especially phased-array antennas are in discussion.
With increasing frequency, the physical area required for such phased arrays continuously decreases and allows a high integration of respective solutions. Therefore, more attention has to be given to testing the antenna diagrams/beams than with today's technology. Especially, a dynamic adaptation has to be checked. Also, current measurement techniques are typically performed using network analyzers connected by coaxial cables to the device under test. When using highly integrated active antennas, however, such an interface may no longer be effective for performing antenna measurements. When testing devices under test in a lab environment, measuring devices are connected via physical cables with the device under test, which generally results in a stable and reproducible measurement environment. The antenna, however, is generally not used in such measurements. Instead, the test of the antenna implementation is typically performed in a separate measurement.
With 5G technology, however, the active antenna will be an integral part of the device under test. Parameters, such as output power, neighbor channel influence and modulation accuracy, can only be accurately measured taking the antenna into account. Especially, the antenna diagram resulting in the maximum gain direction of the respective antenna-array has to be taken into account.
The patent application publication US20130093447A1 shows a measuring system for performing over-the-air measurements on devices under test. The respective device under test is placed within a device under test holder, which is rotatable by a device under test a rotator. Using a single fixed measuring antenna, measurements are performed. The measuring system according to US20130093447A1 though is not applicable to devices under test that use antenna-arrays, beamforming, antenna diagrams and maximum gain directions of an antenna array. It is therefore not possible to perform accurate measurements on future generations of devices under test using the measuring system of this publication.
The patent application publications EP2354801A1 and DE102006045645A1 show respective holders for testing mobile phones that similarly cannot be applied for devices under test that use antenna-arrays, beamforming, antenna diagrams and maximum gain directions of an antenna array.
What is needed, therefore, is a measuring system and method for performing accurate measurements on communication devices that employ antenna-arrays (e.g., a phased array antenna system).